As soon as we approach the exit, a thick, black wall of smoke covers us. The planes above us are burning the field with fire. There are scattered remains of the planes shot down with the SAM turret, but the number is nothing compared to the army of planes on top of us.

-          Mirai, what do we do?

-          Open the arsenal and summon a Gas Mask. I will summon a Frost Gun to cool down our path, then we find higher ground.

  We run through the thick layers of smoke. The cold beams of the Frost Gun help to extinguish the fire and cool down the temperature a lot, but it still feels hot. After we get out of the smoke, there is a forest in front of us to hide in, and we manage to get away from the bombardment, as well as reach the cliff. We get a clearer view.

-          The SAM turret is very durable, but we need a counterattack plan. Yuusha, trigger the EMP device.

-          Yes. - I take the EMP device out and activate it.

  An electromagnetic pulse pierces the sky. The planes in the sky start to lose direction, and some of them are falling. Intruders emerge from the planes, holding weapons. Mirai takes out a plasma sniper rifle.

-          Yuusha, you deal with the Intruders on the ground. I would be dealing with the flying units.

-          Got it. Please send a signal if I need to retreat.

  I hold my gun tightly, and I track the way back to the battlefield. Finding a good corner, I sneakily shoot down the Intruders one by one. Not long after I can kill some of them, the other Intruders notice me. About sixty eyes glare at me. Full of vengeance. My chest is full of laser-red dots.

  Just when I think my life will end in the first mission, a missile coming from above flies past me. I can feel the heat, as vividly as my first-ever trial. The next moment, everything in front of me is blown up, and small pieces of dust, sand and rock shoot up in every direction, covering the field with smoke again. My spectacle vision lights up again.

-          Yuusha, use your gun to kill the Intruders up close. They are technically immune to normal physical damage.

-          Roger that.

  I dash out of the hidden corner and approach the confused Intruders. I quickly take their lives with my last few loads in the magazine and retreat.

-          Good job, Yuusha. The field is clear. We will retreat before further reinforcements arrive.

  Utilising the time frame we secure from clearing their first wave of reinforcements, we have safely reached the plane, and we fly back.

-          It will be another fifteen minutes, so I will just briefly summarize what we got for today's training mission. Firstly, we manage to identify more towers that we do not know existed before, and we will deal with them later. Some of them are in very remote places, such as this island, while some are in places that you would never be able to imagine...

  And we get back home, not having any major injuries. Just a bit of scratch from the flying rock fragments, but I can treat it easily.

__________________

  2050, Counter-Extraterrestrial Association Headquarters, New York City

-          Lieutenant Colonel, an anomaly was detected at 26 degrees North, 142 degrees East, near the Ogasawara Islands area. Recently, our satellites near the region receive mysterious signals, and now all of them seem to suffer from an EMP attack, and temporarily stop working.

-          Noted, Sergeant. Deploy Units 1 and 2 from sub-division 1, Asia branch to investigate the area. Concentrate offensive satellites Unit J1 to these regions in case things go bad. We have been tracking this entity for quite a long time already. Do not let anything escape!

  This is the atmosphere of the Counter-Extraterrestrial Association, CEA, a government-funded multi-national association that has been protecting the well-being of humanity against foreign threats. Their headquarter majestically sits in the centre of the prosperous New York City, continually sending satellites, planes and signals across many more branches around the world. The office is a huge room, filled with all kinds of cutting-edge devices and control panels. Every minute, the clock keeps ticking, and officers run around, continue collecting more vital information, as if their lives depend on it. Literally, the fate of humanity also depends on them.

    Lieutenant Colonel walks around the room, smoking a piece of cigarette, a satisfied smile on his face. He takes out a communication tablet, sending information regarding the traces of Intruders to other branches. Working nearly twenty years as a top member of CEA, he is full of experience, solving mystery after mystery. And this may be his next one.

-          Everyone! Continue to work! Your blood, sweat and tears will pay off when we return the alien threats to their pitiful nest!

-          Sir, yes, sir!

___________________________

-          Yuusha, I have collated every piece of information into the Codex. You can read them anytime. By the way, dinner is ready. Just come down once you finish with your work.

-          Mirai, sometimes, I just feel like you fulfil my life. With you here, I don't even feel like needing a girlfriend...

-          Say one more word and this kitchen knife will be friends with your pitiful skull forever. - Mirai holds a kitchen knife in her right hand.

  I should have programmed a "sense of humour" file and inserted it into her hard drive.

  The evening is strangely peaceful. The carpet of moonlight covers every corner of the metropolitan city, lighting everything. The streets are so empty, that you hear the sounds of the evening breeze. I finish my work, shut down my laptop and have the dinner that Mirai has prepared for me. A plate with classic white rice, with some slices of finely cooked pork and a bowl of vegetable soup using the pork broth, simple but tasty. My past self is surely lamenting his unlucky life before receiving this package.

  Following my perceptually sumptuous dinner, I have a good bath, just to get caught in Mirai's lessons about the Intruders' profile and the usage of items in the arsenal after it.

-          Now, Yuusha. It is time that we seriously need to learn. Sit down.

  Mirai waves her left hand, closing every door and window in my living room. The light dims to a somewhat dark yellow colour. The hologram of various types of Intruders is projected clearly from my three-dimensional television screen. Out of nowhere, she summons a long stick, as if she is a teacher. She points it at the hologram.

-          Intruders are classified into many classes and ranks. Classes decide how they function, and ranks decide their power. This one, which you fought earlier, belongs to the Physical class and Soldier rank, which simply means that they do not have any special abilities besides hand combat and simple weapon wielding. However, they may outnumber you in real combat, so do not let yourself fall into that obvious trap. Any questions?

-          Yes, ma'am. I have a question.

-          Yes, Yuusha. What is your question?

-          When is our break time?

  Swoosh!

  A metal stick flits past my forehead, and I can feel my skin burning from how fast the stick is moving in the air. It hits a ceramic plate full of fruit on it, and the moment the stick makes the impact with the plate, the clangorous cracking sound of ceramic covers the entire room.

-          Again, any questions?

-          No... ma'am...

-          Ok, now, let me introduce to you different classes of Intruders. Physical class does physical damage, no abilities. The engineer class uses advanced technology to wield heavy mechanical weapons, which also have various abilities, but are focused on attacking. Engineer and Physical class will directly fight on the battlefield.

-          Oh, noted.

- The technologist class assists the Engineer class with remote air assaults such as satellites and missiles. They are also in charge of maintaining weapons and devices. The scientist class works in headquarters, and they are responsible for utilising resources extracted from Earth and developing weapons. They can only do brain work, so if you manage to approach close to them, they stand virtually no chance.

-          Yes.

-          Lastly, the Commander class. This one Intruder controls the Intruder army on Earth, and contacts with other branches or the higher entities, which we have no clue about. They seem to have every stat abnormally high, so the only edge we have over them is caution.

  My last few working neurons are begging for mercy, counting down before self-destructing themselves. As if I can survive this long to beat each of them.

-          Ok, now, let's move on to the...

-          Can we stop here? I need some time to digest this new information. - This time, I genuinely ask her to stop.

  I hear a yawn from Mirai. Although being a robot, I see the apparent disappointment on her face. The screen turns off, and all windows and doors open.

-          Haizz... This time I acknowledge that you are exhausted already, so get your sleep. We will continue the lesson tomorrow. - Mirai says and walks towards the charger stand.

  I make sure that Mirai has received the power supply from the stand, and then I go straight to the bedroom. It has been very long since I graduated from my university, and taking lessons for a cause is still a pain.

  The lights are off, and I finally get to bed, exhausted. Maybe I am exaggerating things. Is this brain work supposed to drain so much of my energy? No point thinking about it, anyway.